It is proposed to develop an ophthalmic instrument that will be used to objectively measure contrast sensitivity loss in patients due to intraocular light scattering. The instrument will record the images of blue, green, and red line-patterns from patient's retinas. Computerized image analysis techniques will be used to derive the contrast sensitivity function for each of the colors. Since intraocular scattering is wavelength dependent, comparisons of the objectively determined contrast sensitivity functions among the three wavelengths will reveal the relative extent to which entoptic scattering (strongly wavelength dependent) and ocular refractive errors (not strongly wavelength dependent) contribute to the patient's contrast sensitivity functions. The proposed objective measuring instrument will not require patients to respond to how well they perceive the clarity of test patterns. Such a device should prove to be extremely useful to ophthalmologists and optometrists in the objective assessment of the loss of contrast sensitivity experienced by a wide class of patients including those examined for: pre-operative cataract, corneal disease, contact lens fitting problems, and post-operative radial keratotomy.